PPAPI: Add a warning when URLRequest.SetProperty fails

ppapi/proxy/url_request_info_resource.cc

Index: ppapi/proxy/url_request_info_resource.cc
diff --git a/ppapi/proxy/url_request_info_resource.cc b/ppapi/proxy/url_request_info_resource.cc
index 19d02d726ce1d11f849ea0028c14ef3e6cd9d2d2..a1ba17cc085b7884dad912fe01eb9d3bda3e59c1 100644
--- a/ppapi/proxy/url_request_info_resource.cc
+++ b/ppapi/proxy/url_request_info_resource.cc
@@ -4,6 +4,7 @@
 
 #include "ppapi/proxy/url_request_info_resource.h"
 
+#include "base/strings/string_number_conversions.h"
 #include "ppapi/shared_impl/var.h"
 #include "ppapi/thunk/enter.h"
 #include "ppapi/thunk/ppb_file_ref_api.h"
@@ -66,6 +67,14 @@ PP_Bool URLRequestInfoResource::SetProperty(PP_URLRequestProperty property,
     default:
       break;
   }
+  if (!result) {
+    std::string error_msg("PPB_URLRequestInfo.SetProperty: Attempted to set a "
+                          "value for PP_URLRequestProperty ");
+    error_msg += base::IntToString(property);
+    error_msg += ", but either this property type is invalid or its parameter "
+                 "was inappropriate (e.g., the wrong type of PP_Var).";

[teravest, 2014/12/12 18:39:49]

It should be easy to see if the passed property is a valid value for that enum,
and then the error messages could be more helpful.

It's not that important, though-- I actually feel that it's a little silly to
log to the console for things like this. Should users expect logging messages to
the JS console every time they pass an invalid value in Pepper?

+    Log(PP_LOGLEVEL_ERROR, error_msg);
+  }
   return result;
 }